Steam-actuated valve.



A. MEHLEQRN.

STEAM AGTUATED VALVE..

Anmonmn Hman 0013.5, 190e.

Patented Mar. 2, 1909.

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UNTED ALFRED MEHLHORN, OF DIETRIGI-SDORF, NEAR KIEL, GERMANY.

STEAllf-AC'IUATED VALVE.

Specification of Letters Patent.

Patented March 2, 1909.

Application filed October 5, 1906. Serial No. 337,550.

To all whom, it may concern:

Be it known that l, ALFRED MEnLHonN, a subject of the King of Prussia,and resident of Dietrichsdorf, near Kiel, in the Kingdom of Prussia andGerman Empire, have invented new and useful Improvements inSteam-Actuated Valves, of which the following is a specification.

My present invention relates to improvements in valve gears for directacting steam pumps, of the kind in which at each end of the pump pistonstroke a piston valve is shifted by moving parts of the pump until asteam inlet port is opened, whereupon the piston valve is moved to theend of its stroke by steam pressure alone. An existing device of thiskind has the drawback that the valve piston is kept in a balancedcondition by live steam acting at both ends during the whole stroke ofthe pump, Which, on the one hand, entails a great waste of steam and, onthe other hand, causes the piston valve to be easily displaced byexternal influences. ln addition to this the piston valve so balancedcan only be disposed horizontally, as in the vertical yposition theweight thereof would disturb the action.

According to my present invention, the piston valve of such a pump isloaded by steam at one or the other of the two ends throughout theentire stroke of the pump, and only unloaded toward the end of suchstroke by a mechanically moved auxiliary or slide-valve connecting thesteam loaded end of said piston valve with the exhaust.

In addition to overcoming the above drawbacks the new construction hasthe further advantage that the expansion of the steam, which had beencompressed at one end ofthe piston valve before the balanced conditionwas brought about at the other end of said piston, assists themechanical or direct operation of the piston valve while it is passingfrom the loaded into the unloaded or balanced condition. The mechanicalor direct operation of the piston valve is preferably obtained byproviding inclined tappets on the slide valve, which for its part isoperated by the pump with the assistance of suitable tappets. Saidinclined tappets are given a certain amount of play in regard tosuitable tappets or stops provided on the iston valve, in order toprevent said valve from being mechanically operated until it has beenunloaded or balanced in the manner described.

ln the accompanying drawing my invention is illustrated by way ofexample.

Figure l. is a longitudinal section of the piston valve, showing themanner in which it is mechanically operated by the slide valve. Fig. 2shows a section on the line A-B in Fig. l. Fig. 3 is an elevation of thepump cylinder and valve box showing how the slide valve is operated bythe piston through the agency of tappets.

Referring to Fig. 3, a is the pump piston rod, which carries a fixedsleeve b, to which one end of a lever e, provided in known manner, witha telescopically sliding part, is pivoted, the other end of said leverbeing adapted to operate the valve rod a by being turned up and downabout its fulcrum and striking against the stops c, d.

ln order to unload the piston valve o, the slide valve f (Fig. l), towhich the valve rod a is fastened, when commencing to move by reason ofthe main piston of the pump approaching the end of its stroke, connectsthe channel g with the exhaust port h, by which means the space betweenthe end of theV cylinder and the piston valve end m, of which during thewhole previous stroke on the pump, live steam had acted through thechannel g, is exhausted. At the same time the steam compressed in thecylinder by the end Z of the piston valve o expands, until the pressureat both ends m and Z is the same. When the piston valve o has been thusunloaded through the agency of the slide valve f, the tappet on thelatter bears against the piston valve, until the end l opens the channeli, it being immaterial whether this channel t is opened simultaneouslyby both the slide valve and piston, or firstly by the slide valve andthen by the piston. As soon as the channel i has been opened by thepiston valve end l the latter is exposed to live steam and isaccordingly moved thereby, and, in this way, the pump is reversed.Thereafter the valve piston end m closes the channel g, and the steam isthen compressed at that end of the piston, thus preventing the pistonfrom striking against the cover plate of the cylinder. These operationsare repeated in the opposite direction as soon as the piston of the pumparrives at the opposite end of its stroke.

In the construction shown in the drawing the slide valve operates thepiston valve by means of inclined tappets p, p provided on said slides,which strike against suitably shaped stops g, g on the piston valve.Between the tappets on the slide valve and the stops on the piston valvesuflicient space is provided, to enable the piston valve,

after it has been mechanically moved for a,

certain distance, to complete its stroke under the influence of thesteam, without striking spaces t, t/ of the piston valve, in order to beconducted to the exhaust.

What I claim and desire to secure by Letters Patent is 1. In combinationwith a steam cylinder and yworking piston a steam actuated valve,comprising in combination, a piston valve, a cylinder containing saidpiston valve, a steam chest in said cylinder, two channels connectingsaid steam chest with said cy linder near to each end respectively, anauxiliary valve body adapted to open one of said channels to ltheexhaust before the other channel is opened to live steam, and tappets onsaid auxiliary valve body adapted to mechanically move said piston valvewhen the one of said channels has been opened to the exhaust and beforethe other of said channels is opened to live steam, substantially as,andfor the purpose set forth.

2. Valve mechanism for direct acting steam pumps, comprising incombination, a piston valve to control the steam passages of the steamcylinder', a cylinder containing said piston valve, a steam chest insaid cylinder, two channels connecting said 'steam chest with saidcylinder nearto the opposite ends respectively, an auxiliary valve bodyadapted to `be moved transverse -to the direction of motion of thepiston valve so as to open one of said channels to the exhaust beforethe other channel is opened to live steam, and tappets on said auxiliaryvalve' body adapted to mechanically move 'said piston valve Ywhen one ofsaid channels has been opened to the exhaust and before the other` ofsaid channels is opened to live steam, substantially as, and for thepurposev

